In a preferred application, the invention relates to sealing gaskets or cups intended to be interposed between two coaxial parts, such as, for example, a cylinder and a piston of a brake control hydraulic system.
Within the scope of such an application, in a brake control system, the implementation of a sealing cup is known, for example, which provides a dual function, i.e., a sealing function enabling both chambers located on either side of the cup gasket to be isolated on the one hand and, on the other hand a back flow stop valve function enabling a slight leak, a so-called replenishing leak, from one chamber to the other but on the contrary, preventing any flow in the opposite direction when the system must exert a braking pressure.
For this purpose, the annular cup gasket has an axial <<U>> section which comprises a static sealing annular lip, a dynamic branch defining a dynamic sealing annular lip and a core connecting the static and dynamic branches and defining a bead opposite the lip.
The annular sealing cups, the so-called replenishing cups, according to the prior art generally have a uniform thickness and if they provide their dual function of isolation in one direction and of a back flow stop valve in another direction of operation, they however have the drawbacks of not having a large sensitivity to replenishment on the one hand, so that the pressure difference between both chambers is required to be relatively large in order to lift the dynamic lip and provide this replenishment, and on the other hand, of not having an optimum resistance to wear and tear, and notably to the extrusion phenomenon which may occurring during use and more particularly, at the end of the braking system's life, so that the cups according to the prior art are able to free particles which may change the operation of the system.